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稀土材料的红外和可见量子剪裁对于寻找更好能量效率的发光材料来说都是一个激动人心的发展。发光效率的最大上限值能从100%提高到200%甚至更高。在第一代晶硅太阳能电池与第二代薄膜太阳能电池之后第三代的聚光太阳能电池已成为目前的重点发展方向。现在,利用稀土材料的近红外量子剪裁发光效应有可能较好的解决太阳光谱与太阳能电池光电响应之间存在的光谱失配的问题,因此有可能较大幅度的提高太阳能电池的发电效率,因而具有重要的意义与价值。研究了钒酸钇晶体基质中Yb3+离子的近红外量子剪裁发光现象,测量了从可见到红外的钒酸钇晶体的发光谱、激发谱与荧光寿命,测量发现钒酸钇晶体基质能带在约322.0nm光激发时能导致有效的从钒酸钇晶体基质到Yb3+离子的二级合作能量传递,进而导致了很强的Yb3+离子的985.5nm2 F5/2→2 F7/2的近红外量子剪裁发光,同时,钒酸钇晶体基质的位于430.0nm的发光强度大幅降低。测量发现:(A)Yb(1.5)∶YVO4晶体的430.0nm的荧光寿命值为τA=3.785μs;(B)YVO4晶体的430.0nm的荧光寿命值为τB=22.72μs;研究计算发现总的理论量子剪裁效率上限值为η1.5%Yb=183.3%。
Infrared and visible quantum tailoring of rare earth materials is an exciting development for luminescent materials looking for better energy efficiency. The maximum luminous efficiency can be increased from 100% to 200% or more. After the first generation of crystalline silicon solar cells and the second generation of thin-film solar cells after the third generation of concentrating solar cells has become the focus of the current development direction. Now, the use of near infrared quantum tailoring luminescence effect of rare earth materials may well solve the problem of spectral mismatch between the solar spectrum and the photovoltaic response of the solar cell, so it is possible to greatly improve the power generation efficiency of the solar cell and therefore Has important significance and value. The near infrared emission of Yb3 + ion in Yttrium vanadate crystal matrix was investigated. The emission spectrum, excitation spectrum and fluorescence lifetime of yttrium vanadate crystal from visible to infrared were measured. The energy band of Yb3 + The excitation of 322.0 nm light leads to the effective secondary energy transfer from Yttrium vanadate crystal to Yb3 + ion, which in turn leads to strong near-infrared quantum tailoring of 985.5 nm2 F5 / 2 → 2 F7 / 2 for Yb3 + At the same time, the luminescence intensity of the yttrium vanadate crystal substrate at 430.0 nm is greatly reduced. The results showed that: (A) Yb (1.5): the fluorescence lifetime at 430.0nm of YVO4 crystal is τA = 3.785μs; (B) the fluorescence lifetime at 430.0nm of YVO4 crystal is τB = 22.72μs; The upper limit of the quantum cutting efficiency is η1.5% Yb = 183.3%.